Air conditioning apparatus



C. D. Mfl-CCRACKEN ET AL AIR CONDITIONING APPARATUS Oct 28, 1958 2 Sheets-Sheet 1 Filed Oct. 18, 1954 INVENTORS.

CALVIN D.MACCRACKEN. BYGEORGE N. MILES I JOHN J. RIOUX Q ATTORNEY Oct. 28, 1958 c. D. MaccRAcKEN ET Al. 2,857,747

AIR CONDITIONING APPARATUS Filed Oct. 18, 1954 2 Sheets-Sheet 2 x I I A INVENTORS. CALVIN D MACCRACKEN h @LORGE N. MILES .5 QHN J. RIOUX n m gown/buy @QW ATTORNEY United States Patent v AIR CONDITIONING APPARATUS Calvin D. MacCracken; Tenafly, John Rioux, Woodclitf Lake, and George NrMiles, Tenafly, N. J., assigners toJet-Heet, I'nc., Englewood, N; J.', a corporation of" New York Application October-18, .1954, Serial No. 462,866 retains; c1. 62335) This inventio'n relates" to improvements inair conditioning apparatus, and particularly to an improved apparatus -of-thetype customarily referred-to as a central system:for'conditioning allof-the room'sin a' dwelling or the like The present invention contemplates and its practice provides an air' 'conditioningapparatus of compact configurationpadapted to provide relatively low temperature airat coniparativel-y high'pressure for distribution through a' small* diameter duct system such as is shown, for example in-the-.co-pending application of C. D. Mac- Cracken, filed June 22, 1953, Serial No. 363,210, now

cooled air at relatively 'highpressure and relatively low temperature to thedistribution ducts. Because of the unique arrangement of thepart's, all elements likely to require servicing or. replacement arer'eadily available on one side ofitheapparatus, while" the air intake sections that reqluirecleaning from time to'tirne are fullyexposed on another side of the apparatus. For ease of access tdtheservice side or the air intake side, the distribution outlets are arranged to' project upwardly from the top ofdihe assemblage, whilethe condenser air exhausts from one of the remaining sides;- To insure uniformity of airflow over the 'r'e'lat-ively large condenser coils, the condenser 'air bloweris provided with a partitioned wheel which induces air flow directly" over the condenser coil to the section of the wheel adjacent the coil while inducing a similar airnow overtheremaining portion of the coil td' the other 'sideo f-the'blower'wheel, after passing over andncooling the" compressors. Where the air conditioner is to he'used in conj unction with an air heating unit to supply either heated or cooled air through a common duct system, a uni ue damper arrangement is provided for blocking -oif -th'e unused unit. 6

A more completeunderstanding of the invention, and of further objects and features thereof, can be had by reference" to the following description of illustrative embodiments thereof, when considered in connection with the accompanyin'g d-rawing, wherein Figured is a perspective view of an air conditioning apparatus embodying th nvention, partially broken away toweyeal details of internal construction,

Figure 2 is 'a' sectionview of the plenum chamber, tak'en'o'n" the line 2-2 in Figure 1,

Figured is' a sectional view of the condenser blower, t'ah'en on the line 3''3 in Figure 1, and

Figure 4 is an end view of a portion of the condenser r 2,857,747 Painter o'er. 2s;..1'9'ss* and evaporatorcoils; taken on the line'4--4 in Figure 11 Referring to*the'drawings; there is shown an air conditioning apparatus embodying theinvention. and: corn; prising a substantially "rectangular-"casing 10 including a base pan 12; a top; 15anel"14iandj four side panels 16, 18, 20, 22. While'thefpanelslfi azi" customarily will be insulated, suchinsul a' tion.. has beeniomitted in Figure 1 to simplify the drawing';

Resting on and projectlng upwardly" from the base pan 12 at one side of the unit .is a pair of condenser coil assemblies 24, arranged one behind; the other and having the usual finned tiihingg28for: efficient heattransfer characteristiesi Theco denser" coils are connectedto-receiv'e h'igli'pressure gh temperature refrigera'nt through" separate tubes 30; 32 ffro1n two similar compressors 34,-, 3 *whimare'm umed on springs 37 on the base pan ,1 v conventional, they'are' nots'li'ovvn' or"ds'cribed indetail herein.

The condenser inlet-tubes 30;"32'1ead into the top of the coil assemblies"2'4,26, wherein]heatis extracted from the refrigerant by cooling air which is drawn over the coil'assemblies a'sflhereiinafterdescribed. The condensed refrigerant then flowsjt'hrough a pair of drierfilters' 38, 40 and pressure reducing capillary tubes 42,

44* (or expansionwalyesf, not shown) to a pair of.

evaporator c'oil s"4'6, mounted one behind the Other immediately above the condensers 24,. 26. Like the.

condenser coils 24, 26, the evaporators, are made up of finned tubes for efiicient heat transfer;

In the evaporators 4'6, .48, liquefied refrigerant expands to the vapo'r'phase; withdrawing heat from the air stream drawn over the coils as'hereinafter described,

This air stream"the reby"is'cooled to a' Very low temperature say, ti herder of Fl-for distribution tothe space being air" conditioned.

The arrangement of condenser and evaporator coils-in.

series relationship" relative to the air now is for the purposes of obtaining the rather large: air temperature change that is required'for a distribution system of the type with which the present apparatus is to be used. This arrangement gives a long. '-1han-no,rmal path of: .air flow over the condenser coils to obtain the required temperature' change," which is; substantially greater than in the case of the usual air conditioning, system wherein:

relatively large quantities of air are cooled only to, say, 60* F.. I v

The outlets of the evaporator coils are connected by return lines 50, 52' tothe compressors 34,, 3.6 in the bottom of the casing'10, In order to prevent premature vaporization of the refrigera'nt in-the capillary tubes 4:2, 44, the latter preferably are soldered to the compressor return lines 50, 52 through whichcool refrigerant is returned to the compressors. This insures that: the:

coils 124, 26. The an 54isior the purpose of collecting the substantial quantities of-water which will condense out of the ventilating air is the latter passes over the evaporatorcoils', and distribnting'the water over the condenser c'oils to cool" them by evaporation. Because of the {act that the ventil" m'g'. ail is. Cooled to such a low temperature (approximately 40" F.) in passing over the evaporator o l considerably greater quantities of moisture will be condensed out than in the more conventional, moderate (60 F.) temperature systems.

As the compressors per so are- Accordingly relatively large amounts of water will be available for condenser cooling, which makes the superposed evaporator-condenser coil arrangement with condensate cooling of the condensers particularly advantageous in the system of the present invention.

The side panel 20 on the coil side of the assembly has a relatively large opening 58 in the lower portion thereof for admitting air to the condenser-section. A similar opening in the upper portion of the panel 20 is fitted with a filter 60 through which the ventilatingair will flow on its way to the evaporator coils. .It is, of course, unnecessary to filter the condenser cooling air, as this air simply passes through the unit and does not flow to the rooms of the house. v

A frame made up of channel members 62 extending upwardly from the base pan 12 includes lateral support members 64 from which is suspended a scroll-shaped blower housing 66, enclosing a blower wheel 68 of the squirrel cage or sirroco type. This places the blower housing immediately adjacent to the upper half of the condenser coil assembly. As best seen in Figure 3, the blower housing has inlet openings 70, 72 on opposite sides thereof; one adjacent the condenser coils and the other facing toward the opposite side 18 of the casing. This provides a dual inlet to the condenser coil blower, for a purpose to be explained presently.

As shown in Figure 3, the blower wheel is provided with a central partition 74 at right angles to the wheel axis, which divides the wheel into two separate sections. This results in a substantially equal flow of air into the two openings 70, 72 in the blower housing 66. As a result, the air flow to the blower will be along two substantially separate paths.

One part of the air flowing to the blower wheel 68 will pass over the adjacent upper portion of the condenser coils 24, 26 and directly to the opening 70. The other part of the air will flow over the lower portion of the condenser coils, across the bottom of the housing and over the compressor units 34, 36, and then upwardly into the opening 72 at the opposite side of the blower wheel. This insures a much more uniform flow of air over the entire area of the condenser coils than could readily be obtained with only one sideof the blower being open, because of the relatively long vertical area of the condenser coil. Also, it insures aflow of cooling air over the compressor units.

Above the blower housing 66, the lateral support members carry a mounting base 67 on which is placed a motor 76 for driving the condenser blower wheel 68, the motor being coupled to the wheel by a drive belt 78. A second blower motor 80 is mounted on the base 67 beside the first motor 76, and is directly coupled by a shaft 82 to a second blower 84 which is mounted adjacent to the evaporator coils 46, 48. This second blower is provided to draw the ventilating air over the evaporator coils, and to deliver the cooled ventilating air to the space being air conditioned.

In order to keep the warm, unfiltered condenser-cooling air out of the ventilating air path, the latter is entirely enclosed by duct means 86 which extends from the panel 20, enclosing the evaporator coils, to the second blower housing 84. Also, the evaporator coils, the duct 86 and the blower housing 84 all must be well insulated, as indicated at 88, to prevent condensation or so-called sweating, since the temperatures of these parts will be well below the usual dewpoint of the condenser-cooling air which will circulate around them to some slight extent. Preferably, a return duct (not shown) is provided from one or more of the rooms beingcooled to the evaporator coil inlet opening at 60 in order to bring air of the lowest. possible temperature into this part of the system. The condenser cooling air, however, can be drawn directly into the unit from the basement or other space in which the apparatus is located, provided there is adequate passage for air from the outdoors into said space.

The outlet of the second blower opens upwardly into an insulated housing 90 defining a plenum chamber, the top of which is provided with a plurality of small diameter outlet tubes 92 adapted to be joined to lengths of insulated, flexible tubing (not shown) for distributing cooled air to the rooms of the building. At their outlet ends, the distributing tubes will be connected to registers of the aspirating type (see, for example, U. S. Patent 2,613,587-MacCracken) wherein the cooled air will be mixed with air from the rooms and discharged at moderate temperature and velocity.

Because of the relatively large pressure drop across the deep evaporator coils 46, 48 and in the small diameter distribution ducts, a relatively high pressure blower 84 is required for the ventilating air, together with evaporator coils of adequate depth to give the required temperature drop. In a typical case, for example, the blower 84 may be of a type having a capacityof the order of 500 C. F. M. at a pressure rise (across the blower) of 1.75 inches of Water, drawing air through evaporator coils 46,

48 having an overall width of 20 inches, height of 16.

inches and depth of 6 inches. With this arrangement, the system will supply air to the distribution outlet nozzles 92 at about 40 F, at a pressure of approximately 1.25 inches of water. This is adequate to provide air to the registers at the rooms being conditioned at a temperature slightly above 40 F. and a velocity of about 2000 feet per minute. In turn, this air will be mixed with roomair and discharged from the registers at about 65 F. at a velocity of about 400 feet per minute.

It is also intended that the air conditioner of the present invention can be connected readily in parallel with a high temperature, high velocity warm air furnace (such as is shown in U. S. Patent 2,488,548, for example) which will deliver air to the plenum chamber 90 for winter time beating through a duct 94 which comes into the side 16 of the air conditioner casing near the top. In order to prevent warm air from entering the air conditioner or cool air from entering the furnace, an insulated valve plate 96 is provided for closing off the warm air inlet 94 when the air conditioner is operating and for closing 0!! the cold air inlet 86 when the furnace is operating. To this end, the valve plate 96 is hinged in the plenum chamber on a shaft 98 or the like, on which it is freely swingable between a first position closing off the warm air inlet 94 and a second position closing off the cold air inlet 86. Because of the relatively high pressuretapproximately one inch of water minimum) and high velocity at which air will enter the plenum chamber from whichever unit is operating at any given time, the valve plate is arranged to be solely air-pressure-actuated, and will automatically seal off tightly the unused inlet to the plenum chamber, without any additional actuators, control levers or the like. Preferably, the plate 96 is provided with resilient surface seals of heat resistant material 98, such as isocyanate or the like. I

Adjacent the condenser blower housing 66, space is provided in the casing for mounting control elements 100, such as are required to govern the operation of the compressor and blower assemblies. While not shown in detail, it may be noted that the controls preferably will include refrigerant pressure sensing means (as well as the usual thermostatic elements in the space being conditioned), preferably connected so that only one of the compressors 34, 36 and sets of coils 24, 46 or 26, 48 will be in use during times when the load on the system is relatively low. As compared with an arrangement wherein a single compressor and coil assembly of suflicient capacity to handle maximum load is used, the dual coil-compressor arrangement has the advantage that the lower capacity compressor will operate for a greater portion of the time, rather than in short, very low temperature cycles as a higher capacity compressor would, and will therefore introduce relatively greater quantities of cooled air to the rooms of the house, resulting in a lower relative humidity in the rooms. When the load is too great for the single compressor and associated coils to handle, the second compressor will be cut in by the thermostat to take up the increased load. It will be understood, however, that certain features of the invention are not limited to a dual compressor system, the latter being presented herein only as a preferred embodiment.

What is claimed is:

1. In an air conditioning apparatus for supplying cooled air to distribution ducts, in combination, an upright casing, a refrigerant compressor located in the lower portion of said casing, a condenser coil in the lower portion of said casing and connected to said compressor to receive refrigerant therefrom, an evaporator coil located above said condenser coil and connected thereto to receive refrigerant therefrom, said evaporator coil being connected to said compressor to return refrigerant thereto, a first blower in the bottom portion of said casing arranged to draw air over said condenser coil and over said compressor, a second blower in the upper portion of said casing arranged to draw air over said evaporator coil, said casing having openings therein adjacent said coils to admit air to said coils and thence to said blowers, walls defining a plenum chamber in the upper portion of said casing and having outlet openings through which to distribute cooled air, duct means directing air flow from said evaporator coil to said second blower and from said second blower to said plenum chamber, said first blower being located adjacent said condenser coil and comprising a squirrelcage blower wheel having a partition therein dividing said wheel into separate, substantially similar sections, and a housing enclosing said wheel and having oppositely disposed inlet openings adjacent the sides of said wheel to admit air to opposite sides of said wheel, whereby to induce air flow to one side of said wheel over that portion of said condenser coil immediately adjacent to said housing and to the other side of said wheel over the remaining portion of said condenser coil.

2. In an air conditioning apparatus for supplying cooled air to distribution ducts, in combination, a casing, a refrigerant compressor in said casing, a condenser coil in said casing connected to said compressor, an evaporator coil located above said condenser coil and connected between said condenser coil and said compressor, first blower means adjacent said compressor coil, second blower means adjacent said evaporator coil and arranged to draw air over said evaporator coil and deliver said air to said ducts, said casing having openings therein adjacent said coils to admit air to said coils and thence to said blower means, said first blower means comprising a squirrel-cage blower wheel having a partition therein dividing said wheel into separate substantially similar sections, a housing enclosing said wheel and having oppositely disposed inlet openings adjacent the sides of said wheel to admit air to opposite sides of said wheel, whereby to induce air flow to one side of said wheel over that portion of said condenser coil immediately adjacent to said housing and to the other side of said wheel over the remaining portion of said condenser coil.

3. In an air conditioning apparatus for supplying cooled air to distribution ducts, in combination, an upright casing, a pair of refrigerant compressors located in the lower portion of said casing, a pair of condenser coils in the lower portion of said casing and connected one to each said compressor to receive refrigerant therefrom, a pair of evaporator coils located above said condenser coils and connected thereto to receive refrigerant therefrom,

said evaporator coils being connected one to each said compressor to return refrigerant thereto, a first blower in the bottom portion of said casing arranged to draw air over said condenser coils and over said compressors, a second blower in the upper portion of said casing arranged to draw air over said evaporator coil, said casing having openings therein adjacent said coils to admit air to said coils and thence to said blowers, walls defining a plenum chamber in the upper portion of said casing and having outlet openings through which to distribute cooled air, duct means directing air flow from said evaporator coils to said second blower and from said second blower to said plenum chamber, said first blower being located adjacent said condenser coil and comprising a squirrel-cage blower wheel having a partition therein dividing said wheel into separate, substantially similar sections, and a housing enclosing said wheel and having oppositely disposed inlet openings adjacent the sides of said wheel to admit air to opposite sides of said wheel, whereby to induce air flow to one side of said wheel over those positions of said condenser coils immediately adjacent to said housing and to the other side of said wheel over the remaining portion of said condenser coils.

4. In an air conditioning apparatus for supplying cooled air to distribution ducts, in combination, an upright substantially rectangular casing, a pair of refrigerant compressors located in the lower portion of said casing, a pair of condenser coils in the lower portion of said casing and connected one to each of said compressors, a pair of evaporator coils located above said condenser coils and connected between said condenser coils and said compressors, a first blower in the bottom portion of said casing arranged to draw air over said condenser coils, said condenser coils being arranged in series in the path of air fiow to said first blower, a second blower in the upper portion of said casing arranged to draw air over said evaporator coils, said evaporator coils being arranged in series in the path of air flow to said second blower, said casing having openings therein adjacent said coils to admit air to said blowers, means defining a plenum chamber in the upper portion of said casing in communication with said second blower and having outlet openings through which to distribute cooled air to said distribution ducts, duct means directing air flow from said evaporator coils to said second blower and substantially isolating the air flow path to said second blower from the remainder of said casing, said first blower comprising a squirrel-cage blower wheel having a partition therein dividing said wheel into separate substantially similar sections, and a housing enclosing said wheel and having oppositely disposed inlet openings adjacent the sides of said wheel whereby to induce air flow to said wheel along two paths, one of said two paths encompassing the remaining portion of said condenser coils and said compressors;

References Cited in the file of this patent UNITED STATES PATENTS 2,121,837 Steinfeld June 28, 1938 2,200,302 Ruff May 14, 1940 2,225,840 Newton Dec. 24, 1940 2,495,861 Newton Jan. 31, 1950 2,581,709 Rogers Jan. 8, 1952 2,661,603 Trask Dec. 8, 1953 2,682,757 Borgerd July 6, 1954 2,699,796 Grindle et a1 Jan. 18, 1955 2,699,922 Herbst Jan. 18, 1955 2,720,150 Lyman Oct. 11, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 2 85'7fl4'7 October 28, 1.958

Galvin DO MacGraeken et all;

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

@OLuTm line for "positions" read portions @2 Signed and sealed this 27th day of January 1959 (SEAL) Attest:

KARL HO NE ROBERT c. WATSON Attesting Officcr v Commissioner of Patents 

